How is the Zakat calculated for an amount of EGP 27,000, distributed between a bank savings certificate and a declining current account, knowing that the father annually pays Zakat on the entire amount?

The zakat on twenty-seven thousand pounds is six hundred and seventy-five pounds, because the zakat on money is a quarter of a tenth (2.5%). This is based on what was reported from Aisha and Ali, may Allah be pleased with them, that the Prophet, peace and blessings be upon him, used to take half a dinar from every twenty dinars or more, and one dinar from forty dinars.